Plastic Wavelength-Shifting Fiber for Long-Distance Small-Diameter Detection
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Solution Overview
Problem
Plastic wavelength shifting fibers face challenges in transmitting light over long distances due to attenuation when the diameter is small, which is exacerbated by the need for larger detection apparatuses.
Innovation Solution
A plastic wavelength shifting fiber with a core containing a fluorescent agent having a specific carbon and oxygen atom count and satisfying a defined overlap parameter and quantum yield condition, along with a cladding of lower refractive index, to enhance fluorescence lifetime and transmission distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the diameter of the wavelength shifting fiber is reduced, then the detection apparatus size is reduced, but the light transmission distance is shortened due to increased attenuation
Solution Approach 1:
The patent applies parameter changes by optimizing the fluorescent agent's molecular structure (controlling carbon and oxygen atom counts within specific ranges) and its spectral properties (overlap parameter between absorption and fluorescence spectra). This modifies the physical-chemical parameters of the fiber material to reduce attenuation and extend light transmission distance even in small-diameter fibers.
Solution Approach 2:
The patent uses composite materials by incorporating a specifically designed fluorescent agent into the plastic scintillator matrix. The fluorescent agent molecules with controlled atomic composition create a composite structure that simultaneously achieves short fluorescence lifetime and reduced light attenuation, resolving the contradiction between fiber diameter and transmission distance.
2Ease of manufacture
If a plastic wavelength shifting fiber is used instead of glass, then manufacturing cost and processing ease are improved, but light transmission performance deteriorates
Solution Approach 1:
The patent changes the material parameters by selecting and optimizing the fluorescent agent's molecular structure (carbon and oxygen atom counts) and spectral characteristics. This enables plastic fibers to achieve light transmission performance comparable to or exceeding glass fibers, while retaining the manufacturing advantages of plastic materials.
Solution Approach 2:
The patent effectively copies the successful wavelength-shifting mechanism from glass fibers into plastic fibers by using a specifically engineered fluorescent agent. This allows plastic fibers to replicate the functional performance of glass fibers while maintaining the cost and processing benefits of plastic materials.
3Measurement precision
If the fluorescence lifetime is extended to improve detection sensitivity, then the signal strength is improved, but the temporal resolution of the detector deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the fluorescent agent's molecular structure (carbon and oxygen atom counts within specific ranges). This optimization achieves a balanced parameter set that provides sufficient fluorescence intensity for good detection sensitivity while maintaining a short enough lifetime for acceptable temporal resolution.
Solution Approach 2:
The patent applies local quality by designing the fluorescent agent with specific local molecular characteristics (controlled atomic composition and spectral properties). This localized optimization of the fluorescent agent's properties enables simultaneous achievement of good detection sensitivity and temporal resolution that cannot be obtained with conventional fluorescent materials.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The fiber achieves efficient light transmission over long distances despite a small diameter by controlling fluorescence lifetime and attenuation, improving detection sensitivity.
Implementation Method 1
An organic fluorescent agent that absorbs blue light having a wavelength of about 430 nm, i.e., absorbs light emitted from a scintillator, and shifts the absorbed blue light into green light having a wavelength of about 550 nm
Implementation Method 2
the outer peripheral surface of a core that absorbs blue light generated by a scintillator and shifts its wavelength into that of green light or the like is covered (or coated) with a cladding having a refractive index lower than that of the core
Data Source
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AI summary
A plastic wavelength shifting fiber includes a core (11) containing a fluorescent agent having a peak of a fluorescence spectrum in a wavelength range of 450 to 550 nm, and a cladding (12) covering an outer peripheral surface of the core and has a refractive index lower than that of the core. A sum of the number of carbon and oxygen atoms of the fluorescent agent is 10 to 25, and a quantum yield QE of the fluorescent agent and an overlap parameter OL thereof defined by Formula (2) satisfy Formula (1): OL×1−QE<0.07 OL=∑i=0200Abs300+2×i×Flu300+2×i here, Abs(300+2×i) is a relative intensity of an absorption spectrum normalized so that its peak intensity becomes 1; Flu(300+2×i) is a relative intensity of a fluorescence spectrum normalized so that its peak intensity becomes 1; and i is a variable that increases from 0 to 200 by 2 at a time.